This invention relates to a door-closure control system, and more particularly to a device that automatically closes the door in response to a predetermined condition.
In the event of fire it is of utmost importance to seal the entrance or passageway to any unexposed corridor, room, or office as quickly and as efficiently as is possible to prevent the fire from leaping into the unexposed area. Most entrances and passageways can be effectively sealed by simply closing the door leading to that passageway. By closing the door, substantially all the flames, gas fumes, smoke, and heat will be prevented from entering the unexposed area. Unfortunately, the door may not be closed in time to prevent catastrophe if the persons in the area are either unaware of the fire in some other part of the building, or are unable to close the door.
In hospitals and nursing homes, elderly persons, invalids, bedridden patients, handicapped and crippled individuals and wheelchair patients may not be able to close the door in the event of fire. Newborn infants and little babies are certainly unable to close any door in the event of fire. In houses, apartment buildings, hotels, motels and the like, individuals who are asleep as well as very young children may be unable to close the door to their rooms in case of fire. In warehouses, libraries, museums, and the like, sections may be temporarily unoccupied so that no one is present to close the door during a fire. At night, many public buildings, such as department stores, office buildings, and theatres have a substantial number of passageways and rooms that are unoccupied and therefore have no one to close the door in case of fire.
In the event of fire it is important to minimize the progress of the fire until firemen can be summoned to the scene to put out the fire. This can be accomplished by quickly enclosing the area being consumed by the fire. Automatic or remote control closing of doors in such areas is necessary to minimize the access of air to the fire. It is well known that even if there is sufficient fuel capable of being ignited, the fire will be extinguished if there is not sufficient air to support combustion.
It is also very desirable to provide for remote control closing of a door during certain times of the day or night. It may also be desirable to provide automatic door closing in response to some other condition, such as flooding.
Furthermore, in hospitals and nursing homes, it is desirable to partially open the door to a desired position so as to allow circulation of air, and to permit nursing personnel to observe the patients in the rooms. In any occupied building, many persons desire to leave their doors partially or completely open for easy ingress and egress and to enable them to observe the area on the other side of the door.
It is well known to provide doors with door checks, either of the hinge-type, usually mounted on the door or beneath the door, or of the surface-mounted type which are secured to the face of the door near the top edge. With either type, opening the door compresses a spring mechanism and expands a hydraulic piston and cylinder combination which fills from a hydraulic fluid reservoir. Sometimes the fluid reservoir is simply a portion of the cylinder on the other side of the piston. In any event, when the opened door is released, a spring urges the door toward the closed position, and the rate of movement of the door is regulated by controlling the rate at which the cylinder can empty. This is accomplished by causing the fluid to pass through passages controlled by one or more adjustable flow-restricting valves. Doors controlled by such mechanisms normally are retained in the closed position, although in some mechanisms, there is provision for holding the door open by such devices as detents which engage if the door is pushed open beyond its normal fully opened position. Conventional door checks of the foregoing type are described in U.S. Pat. Nos. 1,011,287 and 2,024,472. Fire doors are typically held open by a fusible link which melts when overheated and permits doors to close. Examples of such fusible-link fire-doors are described in U.S. Pat. Nos. 1,179,384 and 1,851,260.
Electromagnetic door closures are known wherein an electromagnet holds the door open until the circuit of the electromagnet is interrupted, but such devices do not allow for selective positioning of the door. A complex latching arrangement is shown in an electronically controlled hold-open device in U.S. Pat. No. 3,771,823. A complex hydraulic combined door-checking and door hold-open mechanism is shown in U.S. Pat. No. 3,696,462. While the present invention relates to hinge-type swinging or pivotable doors, and not sliding doors, of interest as showing the state of art in spring and line return mechanisms for sliding doors are U.S. Pat. Nos. 3,160,250 and 3,020,580. U.S. Pat. No. 3,332,638 illustrates a retractor device for closing a sliding door equipped with a band brake to damp the velocity of retraction.
One object of the present invention is to provide an improved door closure device that permits the door to be freely pivoted about its hinges to a desired position once the device is in a loaded or cocked position, so as to allow free circulation of air through the door passageway when the door is opened, permitting nursing personnel to observe patients in their rooms, and facilitating easy ingress and egress into the room, but which will cause the door to automatically close in the event of fire.
Another object of the invention is to provide a new and improved safety device that reliably and efficiently closes a door in the event of fire.
Still another object of this invention is to provide means responsive to the conditions of fire to automatically move a door to its closed position to retard the progress of the fire.
It is another object of this invention to provide an improved door closure device for preventing fire, smoke, gas fumes, and the like from entering the room of a patient who is unable to close the door.
It is also an object of this invention to provide a system for closing a door which may be activated manually or in response to a predetermined condition.
A further object of this invention is to provide an improved door closure device that operates expeditiously, is inexpensive to manufacture, dependable in operation, of simple design and construction, easy to operate, readily installed and removed from operating position, and capable of performing properly after long periods of use.
The foregoing and other objects and advantages of the invention will become apparent from the following description and appended claims.